Method and a device for determining a trigger condition for a rare signal event

Abstract

A method and a device for determining a trigger condition for presenting a registered signal on a display of an oscilloscope on the basis of a rare signal event in the registered signal. The method and device determines a level-based and/or time-based distribution of frequencies of occurrence from level-based and/or time-based parameters determined from sampled values of the registered signal in a specified corresponding level-raster and/or time raster, and compares the determined level-based and/or time-based distribution of frequencies of occurrence with a previously given corresponding level-based and/or time-based reference-distribution of frequencies of occurrence. A first trigger condition is determined dependent upon an identified difference between corresponding level-based and/or time-based distribution of frequencies of occurrence and corresponding level-based and/or time-based reference-distribution of frequencies of occurrence. A trigger signal is activated if the trigger condition in the registered signal has been overstepped or undercut.

The invention claimed is: 
     
       1. A method for determining a trigger condition based on a rare signal event in a registered signal, the method comprising:
 determining a level-based and/or time-based frequency of occurrence of level-based and/or time-based parameters determined from sampled values of the registered signal in a specified corresponding level-raster and/or time-raster; 
 comparing a distribution of the determined level-based and/or time-based frequencies of occurrence with a previously determined corresponding level-based and/or time-based reference-distribution of frequencies of occurrence; 
 determining the trigger condition dependent upon an identified difference between corresponding level-based and/or time-based distribution of frequencies of occurrence and corresponding level-based and/or time-based reference-distribution of frequencies of occurrence; and 
 activating a trigger signal if the trigger condition occurs in the registered signal, 
 wherein the trigger condition is a first level-based and/or time-based threshold value which is to be overstepped or undercut by the registered signal, and 
 wherein the first level-based threshold value or the first time-based threshold value is disposed in a corresponding level-range or time-range of the corresponding level-based and/or time-based parameter in which a difference between the determined corresponding level-based and/or time-based distribution of frequencies of occurrence and the corresponding level-based and/or time-based reference-distribution of frequencies of occurrence is identified. 
 
     
     
       2. The method according to  claim 1 , wherein the level-based and/or time-based parameter of the registered signal is a corresponding level-based and/or time-based statistical parameter of the registered signal. 
     
     
       3. The method according to  claim 1 , wherein the level-based and/or time-based frequency of occurrence is determined from new in each case over successive measuring intervals. 
     
     
       4. The method according to  claim 1 , wherein the level-based and/or time-based distribution of frequencies of occurrence is continuously updated by considering earlier determined portions of the level-based and/or time-based distribution of frequencies of occurrence more weakly in the level-based and/or time-based distribution of frequencies of occurrence. 
     
     
       5. The method according to  claim 1 , wherein the level-based and/or time-based distribution of frequencies of occurrence is continuously updated by removing earlier determined portions of the level-based and/or time-based distribution of frequencies of occurrence from the level-based and/or time-based distribution of frequencies of occurrence. 
     
     
       6. The method according to  claim 1 , wherein the time-based distribution of frequencies of occurrence is determined in each case for different, first level-based threshold values. 
     
     
       7. The method according to  claim 1 , wherein the comparison of the determined distribution of frequencies of occurrence with a previously given reference-distribution of frequencies of occurrence is implemented by means of correlating the determined distribution of frequencies of occurrence with a previously given reference-distribution of frequencies of occurrence. 
     
     
       8. A method for determining a trigger condition based on a rare signal event in a registered signal, the method comprising:
 determining a level-based and/or time-based frequency of occurrence of level-based and/or time-based parameters determined from sampled values of the registered signal in a specified corresponding level-raster and/or time-raster; 
 comparing a distribution of the determined level-based and/or time-based frequencies of occurrence with a previously determined corresponding level-based and/or time-based reference-distribution of frequencies of occurrence; 
 determining the trigger condition dependent upon an identified difference between corresponding level-based and/or time-based distribution of frequencies of occurrence and corresponding level-based and/or time-based reference-distribution of frequencies of occurrence; and 
 activating a trigger signal if the trigger condition occurs in the registered signal, 
 wherein the trigger condition is a first trigger condition and the trigger signal is a first trigger signal, and 
 wherein, with the occurrence of a second trigger condition in the registered signal, a second trigger signal is activated with which a signal portion of the registered signal is acquired in which the rare signal event is identified in a signal post-processing. 
 
     
     
       9. The method according to  claim 8 , wherein, in the case of a rare signal event identified in the acquired signal portion, the acquired signal portion of the registered signal is presented on a display device. 
     
     
       10. The method according to  claim 8 , wherein, if a rare signal event is not-identified in the acquired signal portion, the acquired signal portion of the registered signal is not presented on a display device, and the triggering of the registered signal is released again. 
     
     
       11. The method according to  claim 8 , wherein the rare signal event is identified in the acquired signal portion if the acquired signal portion also comes to be disposed outside a specified mask made from individual, successive time portions, in each case with an upper and lower threshold value. 
     
     
       12. The method according to  claim 8 , wherein a trigger signal with which a signal portion of the registered signal is acquired is activated if the occurrence of the second trigger condition is present in the registered signal and, at the same time, a rare signal event is identified in the signal portion of the registered signal to be acquired. 
     
     
       13. The method according to  claim 12 , wherein the frequency of occurrence of the second trigger condition in the registered signal is determined if, at the same time, no rare signal event is identified in the signal portion of the registered signal to be acquired. 
     
     
       14. The method according to  claim 8 , wherein the second trigger condition is a second level-based and/or time-based threshold value which is to be overstepped or undercut by the registered signal. 
     
     
       15. A device for determining a trigger condition based on a rare signal event in a registered signal, comprising:
 an acquisition buffer with acquired sampled values of the registered signal; and 
 a trigger unit supplied with the sampled values of the registered signal and connected to the acquisition buffer for generation of a trigger signal, 
 wherein a unit for determining a trigger condition is connected upstream of the trigger unit, 
 wherein the unit for determining the trigger condition is connected to a unit for determining a deviation between determined frequencies of occurrence and reference frequencies of occurrence, and 
 wherein the unit for determining the deviation is connected to a unit for determining frequencies of occurrence which is connected at the input end to the input of the acquisition buffer. 
 
     
     
       16. The device according to  claim 15 , wherein a unit for selecting a signal portion of an acquired signal containing the rare signal event is interconnected between the acquisition buffer and a display.